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Date: Mon, 14 Sep 2026 19:58:12 +0300
From: Mike Rapoport <rppt@kernel.org>
To: "David Hildenbrand (Arm)" <david@kernel.org>
Cc: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Nguyen Ngoc Thang <ngocthang2710.1999@gmail.com>,
	Zi Yan <ziy@nvidia.com>,
	Baolin Wang <baolin.wang@linux.alibaba.com>,
	"Liam R . Howlett" <liam@infradead.org>,
	Nico Pache <nico.pache@linux.dev>,
	Ryan Roberts <ryan.roberts@arm.com>, Dev Jain <dev.jain@arm.com>,
	Barry Song <baohua@kernel.org>, Lance Yang <lance.yang@linux.dev>,
	Usama Arif <usama.arif@linux.dev>,
	Matthew Wilcox <willy@infradead.org>, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org,
	Jan Kara <jack@suse.cz>, Hugh Dickins <hughd@google.com>
Subject: Re: [PATCH v2] khugepaged: hold invalidate_lock across
 collapse_file() readahead
Message-ID: <aqgnpAqG_OS7gTeX@kernel.org>
References: <DLEBZ0GIGNQ8.17U563YYJ37AA@nvidia.com>
 <20260913163644.122133-1-ngocthang2710.1999@gmail.com>
 <20260913111700.6de78b5834842f7dd3f12d07@linux-foundation.org>
 <aqbvFtlXd3Jdnfbm@gremlin>
 <00dcd8d2-67f3-4ecd-bd7f-06ba1f9c106a@kernel.org>
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In-Reply-To: <00dcd8d2-67f3-4ecd-bd7f-06ba1f9c106a@kernel.org>

On Mon, Sep 14, 2026 at 04:19:11PM +0200, David Hildenbrand (Arm) wrote:
> > 
> > See https://lore.kernel.org/linux-mm/aqbtfms0_2ULBIT7@gremlin/
> > 
> > I am not really entirely happy with somebody who has sent a flurry of patches
> > across disparate subsystems with no previous track record being in charge of a
> > potentially backported fix.
> > 
> > It's David's decision but I think this fix should be taken over by somebody
> > else.
> 
> IIUC, this patch might be responsible for random CI failures (Mike still
> investigating).

Checkout of this commit in mm-unstable [ 1be399d378b78 ("khugepaged: hold
invalidate_lock across collapse_file() readahead") as of a few hours back ]
'khugepaged all:file $XFS_DIR' fails once in 20 or so runs on my machine.

With this commit reverted, 400 iterations didn't fail.

> So I'd prefer if this is taken over by someone familiar with that code.
> 
> @Willy, @Zi, @Lance?
> 
> 
> -- 
> Cheers,
> 
> David

-- 
Sincerely yours,
Mike.